1. Field of the Invention
The invention concerns an apparatus for capturing an object scene, including an imaging optical system which is pivotable relative to a structure and a detector which is fixed with respect to the structure and on which an image of the object scene is produced by the imaging optical system.
This apparatus may involve a seeking head for a target-tracking missile. The invention however can also be used in relation to an “all-around search arrangement”, that is to say a stationary apparatus by which a large field of view is continuously scanned. Such an all-around search arrangement is described and illustrated for example in EP 0 629 890 B1.
2. Discussion of the Prior Art
In known seeking heads for target-tracking missiles with a detector which is fixed with respect to the structure, an imaging optical system is supported cardanically about two axes which extend substantially perpendicularly to the longitudinal axis or roll axis of the missile, namely about a pitch axis and a yaw axis. In that way the optical system can be pivoted with two degrees of freedom about the detector which is fixed with respect to the structure, and oriented onto a target. An example of such a seeking head is described in DE 34 38 544 C2. In that case the squint angle of the seeking head, that is to say the inclination of the optical axis of the optical system relative to the longitudinal axis of the missile, is limited by the mechanics of the cardanic support arrangement.
Seeking heads are known, in which an imaging optical system is carried in a pitch frame which is pivotable about a pitch axis relative to a roll frame. The roll frame in turn is supported in the structure of the missile rotatably about a roll axis coincident with the longitudinal axis of the missile (see DE 33 17 232 A1 and DE 198 24 899 C1). In those known seeking heads the detector is not fixed with respect to the structure but is provided on the pitch frame. That makes it difficult to take out the signals of the detector.